Hot runner manifold blocks are used to deliver molten plastic material from the injection unit to multiple parison cavities at the injection station. The manifold block typically comes in a variety of designs and styles, but an important goal of each style is to achieve balanced flow of the molten material evenly to all of the parison cavities. Achieving balanced flow is critical to the stability of the bottle-making process and the uniform dimensional and distribution attributes of the bottles produced on the machine.
It is known in the art to attach the manifold block to a large base plate which is then bolted to the lower die set. However, as the base plate directly contacts the hot manifold block and the lower die set, the base plate acts as a heat sink or area of loss through its contact areas with the manifold block. Such heat loss is a direct drain of manifold block heat in the contacted areas and can adversely affect the distribution of molten material to the parison cavities even in the best of manifold block designs.
In accordance with current practice, manifold blocks and their base plates come in many different sizes. While each manifold block and base plate can be designed such that their points of mutual contact optimize thermal characteristics within the space available at the injection station, this is an expensive, time-consuming undertaking. Moreover, material cost is a consideration due to the relatively large size of current base plates.
The intent of the present invention is to eliminate the base plate and replace it with a set of relatively small mounting brackets made of a low thermally conductive material to minimize heat loss from the manifold block. The design, shape and dimensions of the brackets can be standardized to serve manifold blocks of a standard width but various lengths in accordance with variations in the number of parison cavities involved.